Isomorphic React experimentation

Isomorphic Lab


This repo is being used to experiment with writing isomorphic JavaScript apps with React 0.13.X, React Router 1.0.0-betaX and express.

It uses newforms for form display and validation on both ends - this could be done manually with any component which can populate its form fields and display error messages based on its props and state, though.


Data fetching

React Router’s experimental AsyncProps is used to fetch data, with route components defining a static loadProps(params, callback(err, data)) function, which will be called when their route is matched against the current URL.

Title generation (source)

Route components can define a static title attribute or a synchronous getTitle(props, params) function, which will be called when the route is matched against the current URL.

Any async props which will be passed to the component when it’s rendered will be passed as the first first argument to getTitle().

Each handler should only define or return its own portion of the URL. e.g. the top-level component might define the site name as a static title, while a nested blog post component might define a static getTitle(props) which returns the title of the post.

By default, these title parts will be reversed and joined with a mid-dot to form the final title to be included in a <title> element or set on document.title depending on the environment - this is configurable.

Client rehydration

The initial render will make use of AsyncProps.rehydrate() with initial async props provided via a window.__PROPS__ variable when running on the client.

Express middleware (source)


var reactRouter = require('./react-router-middleware')

app.use(reactRouter(routes[, options]))


An object to be passed as options to getTitle() - available options are:

reverse (true) - should title parts be reversed into most-specific-first order before joining?

join (' · ') - string to be used to join title parts.

defaultTitle ('(undefined)') - default title to use if none of the matched route components provide title parts.

Response handling

In addition to performing the common functionality described above, the express middleware handles the following scenarios:

Successful rendering

For a regular, successful Handler render, a 'react' view will be rendered with the following locals:

title - generated document title

html - rendered component output

props - props which were used to render the component, serialised to a JSON string.

Non-GET requests

Non-GET request bodies will be set on the Router’s location state as a body property.

The request method will also be available as a method property.


If is used in an onEnter() hook, this will be turned into an HTTP 303 Redirect response…


…unless the redirect location has been given some state. In this case, the middleware will create a new redirect location and run routing on it.

This can be used to render another route back to the user as a response, e.g. rendering a form with user input and validation errors in response to a POST request which contained an invalid body.


If an error is detected at any time, the middleware will call its next() callback with the error to allow whatever error handling middleware is configured elsewhere to pick it up.

MIT Licensed